1. Field of the Invention
The present invention relates to an apparatus for and a method of forming an image. The present invention more particularly relates to an image forming apparatus and an image forming method with which a printing efficiency does not deteriorate even where a paper of a designated size is not set, etc.
2. Description of the Related Art
An image forming apparatus, such as a copier machine and a printer, generally comprises a plurality of paper feed parts to provide for papers of various sizes.
When a print job containing more than one pages whose sizes are different from each other is to be executed using such an image forming apparatus, papers of designated sizes for the respective pages are automatically fed from the paper feed parts.
For example, in the case of printing image data based on a mixed-originals group which consists of originals having different sizes from each other, a paper size is designated for each page. A paper is supplied into the apparatus from the paper feed part which is selected based on a designated paper size, and image data representing each page is printed on a paper as designated.
However, a user wishing to print originals of various sizes sometimes designates a size which is not available in the paper feed parts. The paper feed part for holding papers of a designated size may be empty in other cases.
One of the known techniques to deal with such a situation is to stop printing with a warning sign turned on until papers of a designated size (paper feed cassette) are supplied. Still, this processing only extends a printing time and accordingly hampers print jobs requested by other users.
Meanwhile, although it is not printing technology for a print job including multiple pages of various sizes, another known technique is to ignore the designated size and print in a currently selected size. While this does not extend a printing time longer, this results in printing on papers of an inappropriate size regardless of whether this is allowable and therefore requires later a separate labor for re-printing after supplying papers of an appropriate size.
Still other known technique (Japanese Patent Application Laid-Open Gazette No. 9-314925) is to store in a memory device data representing a page for which a paper of a size not available in the paper feed parts is designated and to thereafter print data which represent a page whose paper size is available in the paper feed parts as priority printing. This processing prevents printing on a paper of an inappropriate size without increasing a printing time.
However, the technique described in the gazette above demands to print while skipping data representing a page for which a paper of a size not available in the paper feed parts is designated. With such an apparatus, after printing data which represent a page whose paper size is available in the paper feed parts as priority printing, papers of the designated size for example must be supplied and the data stored in the memory device must be there after printed, which is an extra labor. In addition, after printing the stored data on a paper of the appropriate designated size, it is necessary to sort the printed sheets in the order of pages while confirming the directions of the originals. This is cumbersome and tends to induce a mistake.
For this reason, some users wish to print for the time being all pages on papers of a size available in the paper feed parts. In this case, one approach is to print a page of a size not available in the paper feed parts in a reduce size, for instance, so that an entire page is printed. When the page is printed on a paper of a size available in the paper feed parts in such a manner, the pages are printed in order, if not necessarily with right image sizes.
Nevertheless, some uses can not endure printing on a paper of a different size from a designated size, which requires some solution.